Split reduction device



Dec. 4%, 192s.v

T. H. THOMAS SPLIT REDUCTION DEVICE Filed Nov. 27, 1926 BY 9% W/ 41 s A M o H H T M O H T 6 2 8 0 20 ()n 'object of my invention is to provide an provided to control the venting of fluid under 75 Patented mes. 4, 192. p i

Ulhlll-TQ fi yl THOMAS H. THOMAS, F EDGE'WOOD, PENNSYLVANIA, ASSIGNOR TO THE WESTING- HOUSE AIR BRAKE COMPANY, OFWILIVIERDING, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA.

SPLIT REDUCTION nnvron.

Application filed November 27, 1926. Serial No. 151,087.

This invention relates to fluid pressure prise a casing, having a piston chamber 16, brakes and more particularly to a devlce for containing a. piston 17 adapted to operate a effecting a reduction in brake pipe pressure slide valve 18 contained in valve chamber 19. in two stages. The split reduction valve device 3 mav In a prior application of Thomas H. comprise a casing, having a piston chamber 60 Thomas and Earle S. Cook, Serial No. 109 20 containing a piston 21, and a piston cham- 04 1. filed May 14, 1926, means are disclosed ber 22 containing a piston 23, said pistons for automatically eflecting a reduction in being connected together by a stem 24 and brake pipe pressure in twostages, so that corhaving differential areas. The valve chamresponding successive applications of the her 25, intermediate the pistons 21 and 23, 65 brakes are produced. This is accomplished contains a slidevalve 26 adapted to be operby first automatically connecting the usual ated by said difl'erential pistons, and said equalizing reservoir to a first reduction reserchamber is constantly open to the atmosphere voir to'effect an initial reduction in brake pipe by way of passage 27. Said casing also has pressure, and a corresponding application of a piston chamber 28 containing a. piston 29 70 the brakes, and then to a second reduction adapted to operate a slide valve 30 contained reservoir to effect a second reduction in in valve chamber 31.

. brake pipe pressure and a further applica- The magnet valve device 6 may com rise a tion of the brakes. magnet 32 adapted to operate a va-ve 33 improved split reduction device of the above pressure from the piston chamber 16 of the character in which means are provided for application valve device 2. W hen the mag ensuring that the second reduction reservoir net 32 is energized, the valve 33 is seated, and will not be connected to theequaliz'ing reserwhen said magnet is deencrgized, the presvoir until the first reduction in brake pipe sure of spring34 unseats valve 33. so pressure has been completed. When the train is running under a clear Another object of my invention 1s to prosignal indication, the train control appavide means for ensuring that the operating ratus is effective to cause the magnet 32 to be parts will be maintained in the second reducenergized. With said magnet energized, the

tion position, so long as the second reduction valve 33 is held seated, so that piston chamber is being eflected. I i 16 is .cutoff from the atmospheric vent Other objects" and advantages Wlll be 'ap- "port 83.

parent in the following more detailed de- Fluid issupplied from the main reservoir scription of my invention. through pipe 37 to valve chamber 7 of the 35 In the accompanyingdrawing; Fig. 1 is a brake valve device 1, andalso through pipes diagrammatic sectional View of a fluid pres- 38 and 39 to valve chamber 19 of the applicasure brake equipment embodying my inven tion valve device 2. Fluid under pressure in tion; and Fig. 2 a slightly modified form of valve chamber 19 then equalizes through port one feature ofmy invention. 40 in the'piston 17 and into piston chamber 40 The brake equipment as shown in the 16. thereby permitting the spring 41 to hold drawing, may comprise a brake valve device said piston and slide valve 18 in the release 1, an application valve device 2, a split reducposition, as shown in the drawing.

tion valve device 3, two feed valve devices 4' The feed valve device 5 is adapted to supand 5, and a magnet valve device 6. ply fluid at the reduced pressure-carried in 45 The brake valve device 1 may comprise a the brake pipe, and the brake pipe is charged casing, having a chamber 7 containing a rowith fluid at the reduced pressure through tary valve 8 adapted to be operated by a hanpipe l3, cavity 44 in slide valve 18 or" the apdle 9. Said casing may. also contain an plication valve device 2, pipe45. passage 46 equalizing p ston 10 fo ming a cha er in the brake valve device 1', cavity 47 in the 50 at one side, connected to the equalizing reserrotary valve 8 (with the brake valve device voir 12, and achamber 13 at the opposite side in running position) and passage 48 to the connected to the usual brake .pipe 14. said brake-pipe 14. Cavity 47 is also connected to equalizing piston being adapted to operate a the passage 49, through which fluid at feed discharge Valv 1 i valve pressure is supplied to the equalizing 56 The application valve device 2 may comreservoir 12 and piston chamber 11 of the equalizing piston 10 by way of a pipe 50, cavity 51 in slide valve 18 of the application valve device 2, pipe 52, passage 53, and pipe 54. Thus the equalizing reservoir 12 and chamber 11 are charged with fluid at brake pipe pressure. Chamber 13, at the opposite side oft-he e ualizing piston 10, being connected to the rake pipe 14 through passage the fluid pressures on opposite sides of the equalizing piston are equalized and the discharge valve 15 is therefore held seated.

The feed valve device 4 supplies fluid at the reduced pressure desired for operation of the split reduction valve device 3 to pipe and passage 56, which passage is lapped by the slide valve 18, of the application valve device 2 in its release position.

Piston chamber 20 of the split reduction valve device 3 is connected to the brake pipe 14 through passage 57 while piston chamber 22 is vented to. the atmosphere through a choked port 58 in the brake valve device, so that with the brake valve in running position, the differential pistons 21 and 23 and slide valve 26 are held in the position shown in the drawing, in which position cavity in said slide valve connects passage 60,- from piston chamber 28,- to the atmosphere through the choked passage 61 and the atmospheric exhaust port 62. The timing reservoir 63 is connected through pipe 64 and past the ball check valve 65 to passage 60, and consequently said reservoir is normally maintained at atmospheric pressure.

Valve chamber 31 is connected to the atmosphere through a choked passage 66, passage 67, pipe 68, cavity 69 in slide valve 18 of the application valve device 2, to atmospherie port 77. Atmospheric pressure being present in both the valve chambers 31 and piston chamber 28 of the split reduction valve device, the spring 72 holds the piston 29 and slide valve 30 in the position shown in the drawing, in which position cavity 73 in said slide valve connects passage 74 from the second reduction reservoir 75 to the atmospheric exhaust port 76. The first reduction reservoir 78 is connected to the atmosphere through pipes 79 and 80, cavity 81 in the slide valve 18 of the application valve device 2, to the atmospheric exhaust port 77.

' If the traflic conditions are unfavorable, the train control apparatus operates to cause the deenergization of magnet 32, and the pressure of spring 34 then unseats the valve 33 so that fluid is vented from piston chamber 16 of the application valve device 2,

through pipe 82 to passage 83 and the atmosphere. Fluid under pressure being thus vented from chamber. 16, fluid at main reservoir pressure in valve chamber 19 causes the piston 17 to be shifted, against the pressure of spring 41, to the application position.

Piston 17, moving to application position, shifts the slide valve 18 to a position in and 86.

which communication from pipe 43 to the brake pipe 14 is cut oil, so that further supply of fluid from the feed valve device 5 to the brake pipe is prevented.

In the application position of the slide valve 18, cavity 51 connects pipe 52 from the equalizing reservoir 12 and chamber 11, at one side of the equalizing piston 10, to the choked passage 84 which leads to pipe and the first reduction reservoir 7 8; Fluid under pressure in the equalizing reservoir 12 and the equalizing piston chamber 11 then equal-- izes into the first reduction reservoir 78, thereby permitting the higher brake pipe pressure in chamber 13 to shift the equalizing piston 10 so as to open the discharge valve 15.

When the discharge valve 15 opens, fluid under pressure from the brake pipe 14 discharges into pipe 85 at a greater rate than it can flow to'the atmosphere through the choked passage 58, and thus the pressure is built up in pipe 85 and piston chamber'22.

The area of piston 23 being greater than the area of piston 21, when the fluid pressure in chamber 22 has been increased to a pre determined degree relative to the brake pipe pressure in chamber 20, the piston 23 is shifted and the slide valve 26 is moved to a position in which cavity 59 connects passages 60 In application position, cavity 69 in slide Valve 18 of the application valve device 2, connects pipes 56 and 68, so that fluid under pressure from the feed Valve device 4 flows through pipe 68, passage 67 ,and achoked passage 66 into valve chamber 31 and also through cavity 87 in slide valve 30, passage 86, cavity 59 in slide valve 25, and passage 60 to piston chamber 28. The piston chamber 28 and valve chamber 31'"'thus become 10;, charged to the same pressure, so that spring 72 holds the piston 29 and slide valve 30 in the position shown in the drawing.

Fluid under pressure also flows from passage 60, through a. choked passage 88 and in) pipe 64 to the timing reservoir 63, thus. charging said reservoir.

When the brake pipe pressure has been reduced by flow through the exhaust port 58 to a degree slightly less than the pressure in the equalizing reservoir 12, as reduced by equalization into the first reduction reservoir 78, the equalizing piston 10 operates in the usual manner to close the discharge valve 15 and thus prevent any further reduction in 12;) brake pipe ressure.

The discharge valve 15 being close-d. fluid under pressure in piston chamber 22 of the split reduction 'valvc device] continues to vent to atmosphere through the choked pas- 12.3 sage 58, so that the pressure in said chamber is reduced until the brake pipe pressure :in piston chamber 21) acting on piston 21 is'sutiicient to shift the pistons 21 and 23 upward- 1y. Said pistons move the slide valve 26 so lit) that cavity 59 connects passage 60 through the choked passage 61 to atmosphere through exhaust port 62. Piston chamber 28 and the timing reservoir 63 being connected to passage 60, fluid under pressure in piston chamber 28 and the timing reservoir 63 is vented to the atmosphere.

tained in their outer positions, even in case the ditferential pistons 21 and 23 should cause movement of the slide valve 26 such as to cut off the exhaust port 62 from piston chamber 28.

lVith the slide valve 30 in its outer position, cavity 90 connects passage 91 and pipes 79 and with passage 74 and the second re duction reservoir 75. Fluid under pressure in the equalizing reservoir 12 and in the first reduction reservoir 78 then equalizes into the second reduction reservoir 7 5, so that the fluid pressure in the equalizing piston'chamher 11 is correspondinglyreduced, causing the higher bake pipe pressure in chamber 13 to operate said piston and again-open'the discharge valve 15, so as to effect a second reduction in brake pipe pressure and a consequent second application of the brakes.

The discharge of fluid from the brake pipe into pipe and to piston chamber-'22 causes the differential pistons 21 and 23 to be shitted, and thereby the slide valve 26, in the same manner as during the first reduction.

In making the second reduction in brake pipe pressure, however, the piston 29 and slide valve 30 are inthe lower position. so that although the slide valve 26 is shifted to the lower position, in which passage 86 is connected to passage 60, the slide valve 30 being new in its lower position, cuts otl' communication from passage 86 to passage 67. Consequently the piston 29 is maintained in its lower position by reason of the connection of piston chamber 28 through passage 89 with exhaust port 76.

\Vhen the brake pipe pressure in chamber 13 at one side of the equalizing piston 10, has reduced to a degree slightly less than the reduced pressure'in the equalizing reservoir and in chamber 11, the equalizing piston 16 again operates to close the discharge valve 15. IVhen the magnet 32 is again energized. valve 34 isshittcd to its seat. Fluid under pressure from valve chamber 19'then cqualizcs through port 40in piston 17 into piston chamber 16. The spring 41 then shifts the piston 17 and slide valve 18 to release posi- 'tionfin which the brake pipe 14 and equalizing reservoir 12 are recharged, causing a consequent release of the brakes. The first and second reduction reservoirs and the timing reservoir are also vented to the atmosphere, and in fact the parts are all restored to-their normal release positions in the same manner as hereinbefore described in connection with the initial charging of the equipment.

Instead ofcontrolling the operation of slide valve 26 by means of differential pistons adapted to be operated by fluid under pressure vented in the opening movement of the discharge valve 15, a corresponding slide valve 26 may be mechanically connected to the discharge valve 15 by a stem 36, as shown in Fig. 2. With this construction, when the discharge valve 15 is moved to open position, the slide valve 26 is also moved.

In normal release position, as shown in Fig. 2, passage 60 is connected to exhaust port 62, as in the case with the construction shown in Fig. 1. When the slide valve 26 is moved with the discharge valve 15. as said valve opens, passage 60 is connected to passage 86, so ,that the same connections are made, as in the Fig. 1 construction.

From the foregoing description of the con- 'struction and operation, it will be apparent that the first and second reduction reservoirs are normally disconnected and are not connected until after the timing reservoir pressure has reduced to a predetermined degree following the first reduction in brake pipe pressure, thus ensuring against the possible venting of fluid from the equalizing reservoir into the second reduction reservoir while the first reduction in brake pipe pressure is being effected.

It will also be noted that piston 29 and slide valve 30 are maintained in the second reduction position,independently ofthe possible movement of the diiierential pistons 21 and 23, and that piston 29 will not be moved back to its normal position until the application piston 17 is moved back to normal release position, in which valve chamber 31 is vented to the atmosphere through pipe 68. cavity 62) in slide valve 18 and exhaust port 71.

The feed valve device 4, in addition to the usual feed valve device 5, is provided for the reason that the same constant pressure, for

, example 60 pounds, is desired at all times for use in the split reduction valve device 3, while the usual feed valve device 5 may be adjusted to maintain ditterent pressures in the brake pipe. according to the class of service in wl'iichthe train may be operating.

llaving now described nrv invention. what I claim as new and desire to secure by Letters Patent. is:

1. In a fluid pressure brake. the combination with a brake pipe. of two reduction reservoirs, means operated upon a venting of fluid under pressure into either reservoir for efiecting a reduction in brake pipe pressure, one reservoir being connected for venting purposes only after the venting of fluid from the. brake pipe due to venting of fluid under pressure to the other reservoir has ceased.

2. In a\fluid pressure brake, the combination with abrake pipe, of a first reduction reservoir, a second reduction reservoir, and means for first venting fluid under pressure to the first reservoir to effect a reduction in brake pipe pressure and then to the second reduction reservoir to effect a second reduction in brake pipe pressure, said reservoirs being connected the one to the other only after the first reduction in brake pipe pressure has been completed.

3. In a fluid pressure brake, the combina tion with a brake pipe, of a first reduction reservoir, a second reduction reservoir initially out of communication with the first reservoir, and means for first venting fluid under pressure to the first reservoir to effect a reduction in brake pipe pressure and then only after the first reduction ceases to the second reduction reservoir to effect a second reduction in brake pipe pressure.

4. In a fluid pressurebrake, the combination with a brake pipe, of a first reduction reservoir, :1 second reduction reservoir, a valve device having a posltion 1n whlch the first reduction reservoir is connected to the second reduction reservoir, and valve means having one position for connecting one side of said valve device to the atmosphere and another position in which fluid under pressure is supplied directly to said valve device.

, 5. In a fluid pressure brake, the combination with a brakepipe, of a first reduction reservoir, a second reduction reservoir, an equalizing reservoir,'a valve device having a position in which. the first reduction reservoir is connected to the second reduction reservoir, and valve means having one position in which one side of said valve device is'connected to the atmosphere and another position in which the first reduction reservoir is connected to the equalizing reservoir and one side of said valve device is directly connected to a source of fluid under pressure.

6. In a fluid pressure brake, the combination with a brake pipe, of a first reduction reservoir, a second reduction reservoir, an equalizing reservoir, a valve device having a position in which the first reduction reservoir is connected to the second reduction reservoir, valve means having one position in which one side of said valve device is connected to the atmosphere and another position in which the first reduction reservoir is connected to the equalizing reservoir and said side of said valve device is directly supplied with fluid under pressure, and asecond valve device having one position for connecting the opposite side of said first valve device to the atmosphere and another position for supplying fluid under pressure to said opposite side only when said valve means is in the position'for connecting the first reduction reservoir with the equalizing reservoir.

7. In a fluid pressure brake, the combina tion with a brake pipe, of a first reduction reservoir, a second reduction reservoir, an equalizing reservoir, an application valve device having an application position, in which the first reduction reservoir is connected to the equalizing reservoir and having a release position, a valve having a position for connecting the first reduction reservoir to the second reduction reservoir, a piston subject to the opposing pressures of a piston chamber and a valve chamber for operating said valve, said valve ,device being adapted in application position to directly connect said valve chamber with a source of fluid under pressure.

In testimony whereof I have hereunto set my hand.

' THOMAS H. THOMAS. 

